- Expansion that even the expansion program would lead to'an excess of fissionable Progran material in 5-7 years, and (2) great advantages are to be gained from the Weapon Require- flexibility-in weapon designs permitted by an adequate supply of fissionable ments ‘material. For example, the use of 30-inch weapons delivered by fighters might lead'to enormously greater effectiveness than 60-inch weapons delivered by bombers. It 4s very important to keep such design parameters free, and not limited by the amount of available material. Mr, Whitman again expressed his position against the concept that one can predict a limit to the number of bombs needed. One must have tremendous numbers on hand, far greater than the number which will actually be shot. The sentiment of the Committee was that it would be unfortunate to discontinue Portsmouth, and that the point of weapon flexibility was particularly important. At 9:35 a.m. the Comittee met with Captain J. A. Waters, Mr. F. Security Hammack, Mr, Boyer, and Mr. W. J. Williams, to discuss the Commission's Clearances security clearance policies, Dr, Rabi explained that the Committee was interested in the clearance policies for scientific personnel, and’in such matters as the time required to ottain clearances, the use of the Nationel Laboratories for unclessified rescerch, etc, Captain Waters reviewed clearance process, required by law for access to restricted data. Security clearance is It is granted on the basis - of an investigation by the FBI or the Civil Service Coumission of the individual's character, loyalty, and associations, An FBI investigation is required for access to the more sensitive areas of information, as determine by the Commission, An FBI investigation takes about 45 days and costs $205. A Civil Service investigation costs $196. Dor FARCRY Cr

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